Circulating heater



Jan. 25, E933. G. D. MATTHEWS CIRCULTING HEATER Filed Dec. 15, 1935 2 sheetsfsheet `1 "IIIIIIIIII dn m, @N f a rm Jan. 25, 1938.

CIRCULATING HEATER Filed Dec. l5, 1955 2 Sheets-Sheet 2 AVio Patented Jan. 25, 1938 UNITED STATES CIRCULATING HEATER George D'. Matthews, Chattanooga, Tenn., as-

signor to Tennessee Stove Works, Chattanooga,

Tenn., a corporation of Tennessee Application December 13, 1935, lSerial No. 54,291

3 Claims.

My invention relates to circulating heaters, and more particularly to latches and openers, for stoves, furnaces and the like.

It has been the practice in the prior art of 5 stoves and especially circulating heaters to employ an outer and an inner casing and a door made of spaced inner and outer portions in the side of such casings and hinged thereto for permitting the insertion of coal or other fuel into the inner casing. Ordinarily such a door is maintained in closed vposition by a securing means of such construction that a handle extending from the outer surface of the door may be rotated and may move an inner catch secured to the inner surface of the door whereby it is wedged against the wall of the inner casing thereby holding 'the door in closed position. Examples of this type of construction are disclosed in Sperry, 1,644,900 and Simons, 1,713,782.

' 2 The disadvantage of this type of construction is that the wedge or latch is exposed to the fire where it may be decomposed or consumed by the excessive heat of such re, so that very shortly it Abecomes ineffective 'as a latch and no longer can serve to secure the door. Another disadvantage is occasioned by the necessity for vusing an outer 'handle adapted to be gripped by the hand and turned. The extension of such handle from the door permits impact and contact with other 30; Objects thereby permitting it to be broken or injured to such an extent that it is in no condi- -tion to perform its-proper functions after a very short usage. Furthermore .after some usage this structure is no longer able to maintain the door in tight closed position thereby permitting air to yenter the stove. Each of' these vdisadvantages contributes to avery unsatisiactorylatch.

In the aboveV type of construction one hand must be freeV to release the latch and then -to open the door. This is 'often very inconvenient y especially when the party has a lump of vcoal in each hand.

With a knowledge of the disadvantages and defects in the prior art, I have `as object of my invention ythe use Vof a latch which will eliminate the element exposed -to the ire to be eaten away, the eliminationY of a prominent handle subject to impacts and frequent breakage andthe introduction of a latch which will maintain the door in tight closed .position at all times and-in deference to the wearoi parts whereby eliminating the ingress of air and creation of a draft due to looseness.

' I have for a further object the use .oi a quickly and easily actuated latch which requires only foot movement of its elements in order to insure its operation.

I have for a further object the introduction of a foot actuated means for releasing the latch and additional means for forcing the door to open 5 position after the latch hasbeeri released whereby the party is freexat all times to transport icoal in both hands without inconvenience. s

It is a further object of my invention to -pron vide a door which may be latched in position Vby I0- merely pushing it to closed position, and maybe opened by pulling. f

It is a still further-object of my invention to employ a spring actuated latch for securing the door or doors in closed position, and in .position-l5 ing said spring Where heat from the stove will not attack and effect its resilient properties.

In the prior art such patents as Schutz, 1,256,- 934, disclose spring actuated latch means coop-,x erating with ibeveled surfaced seats -for maintaining' a `door in closed and ever in sealed position. While such a llatch might be conveniently used for'largedoors suchas ice closures, it would be undesirable for small ones and especially for stoves as manual means must ybe provided for releasing the latchfand heat from the stove would destroy the resilient properties vof the spring.

Foot actuated opening means for doors have been in use.' The patents to Stevenson etal., 911,175 and Tower 533,571 have been employed for large doors to rooms. However, theyghave no application to small structures such as stoves since radically ldifferent in structure from those' necessary to meet the requirements yof a stove'for other device having a small door. Furthermore the heat from -the stove would destroy the resilient properties of the springs. There would *be no place 4for the foot lever rand no way'of joining it to the latch for a stove.

Hunt, 1,694,686 discloses means operated bythe 40 foot for releasing the latch but discloses neither a spring pressed latch nor means for 'opening the door after the latch has been released. Brewer, 720,399, discloses a means operatedlby a piston. and valve for opening a 'furnace door.

Although spring actuated latches and latch releasing means have been known, it is my beli'ef that I have been the first to recognize that it would be possible and desirable to apply a latch to a stove and to provide auxiliary means for cooperating with it to produce the above enumerated new and unexpected results. y

Other objects and advantages of my invention will appear in the following specification,` and ticularly pointed out in the annexed claims.

Figure 1 shows a perspective of a `circulating heater, partly in section, employing the preferred embodiment of my invention. Figure 2 shows a plan View of a circulating heater incorporating the same form of my invention in it. Figure 3 is an enlargement of the lug showing its contour. Figure 4 is a perspective of a part of a circulating heater, partly in section, disclosing a modified form of my invention. Figure 5 is a perspective of part of a circulating heater, partly in section, disclosing a modified form of my invention. Figure 6 discloses a detail of my foot operating mechanism, Figure 'l discloses a plan view of a` modified form of a door operating means.

In the drawings I designates an inner casing which forms a combustion chamber about one extremity of which a ange 2 extends around the entire outer surface and serves to space it from an outer enameled casing. A door 3 is secured to the inner casing and is comprised of two spaced parts, the inner being of the same material as the inner casing, and the outer coated with enamel. From the free end of the inner part of said door extends a lug 4 of such configuration that the top surface is flat and the lower part is formed of oppositely beveled surfaces 2I, 22. To the inner casing is secured a pivot arm 6 upon one endl of which a roller 5 is mounted. The bracket 'I positions the arm B, and to the otherrend of the arm is secured a rod 9 through an opening in the transverse portion 8. The other end of said rod passes through a housing I secured to flange 2, in which housing is seated compression spring II. A nut I2 is screw threaded to rod 9. The fuel door 3 is supported by a hinge I having an outstanding portion with an opening therein for the reception of an end of a rod I6 whose free end extends through the outer casing for insertion into a compression spring I'I, and I8 designates a knob secured to rod I6 for maintaining spring I1 in normal slightly compressed condition. I9 designates a shoulder on casing I for preventing door 3 from being raised by the-action of the Alatch arm 6. 2U represents a knobv or handle on `door 3 for opening, and 23, 24, 25, 26, 21, 28, 29, 3B, and 3l designate a similar spring actuated latch system for the ash door of a circuf lating heater.

This form of my invention in its operation is somewhat as follows:

In opening the fuel door by hand, the party grips knob 2l] and pulls. This force moves the door outwardly by causing roller 5 to move over surface 2| rocking arm downwardly, and rod 9 upwardly by causing spring I I to be compressed to a greater degree. Upon reaching the end of surface 2| and the beginning of surface 22 the roller` moves faster and kicks the door slightly for in moving up surface 22 the spring acts on rod 9 to rock arm 6 and move roller 5 up across the surface forcing the lug outwardly. After l this no additional force is required to swing the door to open position for spring I 'I expands, moving rod I6 through the opening in the outer casing carrying the outstanding portion I5 in the same direction, and swinging the door to open position.

The door is closed by merely pushing or slamming it. Upon reaching the latch, lug 4 is engaged by roller5 von surface 22, and such roller Ythe novel features of the invention will be paris forced downwardly as it rides over this surface, thus swinging arm 6 on its pivot, and raising rod 9 compressing spring I I. After this the roller passes on and rides upwardly on surface 2|, spring II moves rod 9 downwardly and rocks arm on its pivot thereby moving roller 5 as far along surface 2I as possible. However, movement of roller 5 along surface 2l is limited by the engagement of door 3 with casing I, but the door is always urged to tight sealed position against casing I by the action of spring II acting through arm 5 and roller 5. Therefore, ingress of air at the door is always reduced to a minimum and the effectiveness of the seal is not destroyed by wear.

The operation of the latch for the ash door is similar to that employed for the fuel door above described.

When the hands of the party are not available for opening the fuel door, he may employ the foot to exert pressure upon the pivoted lever I3 which causes it to rock, and acting through nut or abutment I2 force lever 9 upwardly and move arm 6 about its pivot, thus moving roller 5 downwardly out of contact with lug 4 and removing the latch action. This leaves rod I6 and spring I'I free to force door 3 to open position, whereby fuel may be inserted. The foot is removed from the lever as soon as the lug 4 clears roller 5 and moves towards open position. The door is again closed in the manner above described.

Instead of using the door opening means of Figures 1 and 2, a modified form disclosed in Figure 7 may be employed. An extending lug I5 from the hinge may cooperate with rod I6 and be actuated by a tension spring I'I secured at one end to the inner wall of the outer casing and at the other to the free end of rod IB. In this form spring Ii' is always in expanded position and has a tendency to contract. As it contracts the lug I5' is moved and the door swung open.

In the modification of Figure 4 the roller 5 moves over the end of lug 4' on oppositely bev-v eled surfaces to lock the door 3 in closed position. 6 designates the arm upon which roller 5 is mounted and said arm is in turn pivotally mounted upon a bracket 'I' secured to casing I. The

' free end of arm 6 is secured to rod 9 whose free end is attached to a tension spring I I on the inner wall of the outer casing. There is no provision made in this embodiment for a foot actuated release lever, however, it is recognized that a number of ways may be employed to release the latch by the foot. The door is opened by simply gripping the knob 2D in the hand and pulling it which forces the roller 5 to move back across the latch surface and release the lug. If desired a door opening means of the type disclosed in Figures 1 and 7 may be employed to swing the door to open position after the latch has been released.

In the modified form of Figure 5 is is unnecessary to employ a lug or shoulder on the casing I to prevent the fuel door 3 from being forced up out of position by the action of the spring actuated arm 6". Roller 5", arm 6, rod 9" and foot lever I3 act in the same manner as in the form disclosed in Figure 1. 34" designates a roller and 35 designates an arm upon which roller 34" is mounted, and which is rigidly secured to casing I. The door opening means disclosed in Figures 1 and 8 may be employed to open the door when the latch has been released.

In its operation a force is exerted on the knob 20 by the hand of the party. This causes the lug 4 to be moved forwardand the roller 5" to move down along the beveled surface swinging lever 6" on its pivot and raising rod 9" thus compressing the spring Il". Roller 34 moves across the at upper surface of the lug 4". When roller 5" moves to the lowermost position of the lug 4 it encounters the upward beveled surface of the lug and under the action of spring It quickly moves across such surface swinging the door outwardly and permitting the door opening means to carry it to open position. The door is closed by pushing or slamming. When the lug 4" engages rollers 5 and 34, the roller 5 is forced down along the lirst beveled surface of the lug 4" while the roller 34 rides across the upper flat surface of the lug 4". The roller 5 passes on to the lowermost point on lug l and then up the oppositely beveled surface of the lug. If there were no roller 34E" the lever 6" acting on lug 4" would force the door out of position upwardly and soon render it unt for closing the fuel opening in casing l". With such roller acting upon the top of the lug this result is impossible, and after long use little or no wear occurs on the upper surface of the lug and the door is continually maintained in the correct position. The same type of latching means is also employed for securing the ash door in closed position.

Figure 6 discloses a detail showing of the foot lever means for releasing the latch. The foot lever I3 has a slot in its body portion for the reception of a lug on the casing which acts as a pivot. ll is a spring which is compressed by the upward movement of the rocking lever i3. l2 is a nut for controlling the compression of spring ll and I4 is a nut for securing an end of lever i3 to rod 9, IU designates a housing or bracket secured to flange 2 for reception of spring II Having thus described my invention, I claim: l. In a circulating heater an inner casing forming a combustion chamber, an outer casing spaced from said inner casing, registering openings in said inner and outer casings, a door closing said openings, said door comprising spaced inner and outer portions for closing said respective openings, latch means supported between the inner and outer casing, and cooperating with said inner door portion to normally maintain s-aid door in tight closed position.

2. In a circulating heater, an inner casing forming a combustion chamber, an outer casing spaced from said inner casing, registering openings in said inner and outer casings, a door closing said openings, said door comprising spaced inner and outer portions for closing said respective openings, latch means supported between the inner and outer casing and cooperating with said inner door portion to normally maintain said door in tight closed position, and means supported by said stove to release said latch.

3. In -a circulating heater, an inner casing forming a combustion chamber, an outer casing spaced from said inner casing, registering openings in said inner and outer casings, a door comprising spaced inner and outer portions for closing said respective openings, latch means supported between the inner and outer casing and cooperating with said inner door portion to normally maintain said door in tight closed position, means supported by said stove to release said latch, and spring means supported on said outer casing to bias said door to open position.

GEORGE D. MATTHEWS. 

